I know that this question is not strictly related to coding, but I'm trusting the knowledge of this community to solve this and I thought it could still interest many people to know how to face this problem.
I am trying to send e-mails to people in a particular company, and keep getting the following error from the mail delivery system:
This is the mail delivery agent at messagelabs.com.
I was unable to deliver your message to the following addresses:
********@******.com
Reason: 554 5.7.1 <********@******.com>: Relay access denied
The message subject was: RE: ********
The message date was: **********
The message identifier was: **********
The message reference was: ************
Please do not reply to this email as it is sent from an unattended mailbox.
Please visit www.messagelabs.com/support for more details
about this error message and instructions to resolve this issue.
Last-Attempt-Date: ********
Remote-MTA: *********
Diagnostic-Code: smtp; 554 5.7.1 <********@******.com>: Relay access denied
Status: 5.7.1
Action: failed
Final-Recipient: ****; ********@******.com
Does anyone know what's going on here? I am trying to send from a normal gmail account, straight from the web browser. It looks like I get this error only when I send e-mails to this specific domain, although we've been e-mailing in the past with no issues at all.
Thank you!